This invention concerns a device to replace rolls and apparatus on rolling stands having rolls supported at one end.
To be more exact, the invention concerns a device or equipment able to grip together the rolls of a rolling stand, whether the stand is horizontal or vertical and also the apparatus or guides for the rolled product and the means which support such apparatus.
It is possible in this way to withdraw such components en bloc at one and the same time, for instance, so as to replace them or for maintenance or to change the type of rolled product to be produced.
According to variants of the invention it is also possible to remove or position the rolls alone or the apparatus alone or else the rolls together with the apparatus, the components being removed or positioned with their reciprocal spacing and alignment maintained as in their working position.
There exists in the known art equipment to carry out the changing of the sets of rolls of a rolling stand having rolls supported at one end. Such known equipment engages only the two rolls and leaves the apparatus and relative supports in position.
The apparatus and supports are removed separately by hand or in other known ways.
According to the known art it is possible to engage one roll at a time or two rolls at a time by means of such equipment, which is moved by a crane or bridge crane or the like.
For instance, French patent No. 1,545,751 (VEB) discloses a movable device able to remove rolling rolls from stands supported at one end and to place them on static support stands, and vice versa.
In fact, a hydraulic gripper is envisaged which is able to engage the top of the cylinder to be removed. This French patent envisages the engagement and movement of one single roll at a time. There are therefore no means able to engage the whole set of rolls and relative apparatus. Movement is carried out by means of a bridge crane type with a rotatable turret.
U.K. Patent Specification No. 1,508,599 (British Steel Corporation) discloses a device to handle heavy rolls, the device being hung from a crane or bridge crane for . movement. Such device comprises fingers with annular protrusions able to grip the roll in correspondence with one of the grooves which shape the rolled bars. The device is actuated by hand and can remove and handle one single roll at a time; in practice, the device is a large gripping device with several jaws.
As indicated above, the known methods for replacing rolls and apparatus envisage that this operation is performed in at least two steps, the rolls being withdrawn separately from the apparatus. This fact entails a considerable waste of time.
Moreover, each element to be fitted has to be aligned in relation to the other elements and therefore this operation requires a successive considerable waste of time and also personnel to carry it out.
Likewise, removal of the rolls and apparatus takes place, in the known art, in an uncorrelated manner and such components are then deposited in a haphazard way.
Thus it is always necessary at a later stage to take the components one by one for re-fitting to the rolling stands thereafter.